From da49e389c41cb0c0925309b6e3af6a8936aa7d69 Mon Sep 17 00:00:00 2001
From: Thomas Kerin <thomas.kerin@bitmaintech.com>
Date: Wed, 6 Sep 2017 14:26:23 +0200
Subject: [PATCH] multisig.input.encodestack - replace OP_0 (permitted by
 partialSignature) with EMPTY_BUFFER

---
 src/templates/multisig/input.js | 7 ++++++-
 src/transaction_builder.js      | 6 +++---
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/templates/multisig/input.js b/src/templates/multisig/input.js
index 79cad91..fbf7a3f 100644
--- a/src/templates/multisig/input.js
+++ b/src/templates/multisig/input.js
@@ -39,7 +39,12 @@ function encodeStack (signatures, scriptPubKey) {
     }
   }
 
-  return [].concat(EMPTY_BUFFER, signatures)
+  return [].concat(EMPTY_BUFFER, signatures.map(function (sig) {
+    if (sig === OPS.OP_0) {
+      return EMPTY_BUFFER
+    }
+    return sig
+  }))
 }
 
 function encode (signatures, scriptPubKey) {
diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index e2a4d86..e6adfd1 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -389,14 +389,14 @@ function buildStack (type, signatures, pubKeys, allowIncomplete) {
   } else if (type === scriptTypes.MULTISIG) {
     if (signatures.length > 0) {
       signatures = signatures.map(function (signature) {
-        return signature || Buffer.from('', 'hex')
+        return signature || ops.OP_0
       })
       if (!allowIncomplete) {
         // remove blank signatures
-        signatures = signatures.filter(function (x) { return x.length !== 0 })
+        signatures = signatures.filter(function (x) { return x !== ops.OP_0 })
       }
 
-      return [].concat(Buffer.from('', 'hex'), signatures)
+      return bscript.multisig.input.encodeStack(signatures)
     }
   } else {
     throw new Error('Not yet supported')